Common Defects: Off-Color Dye Parts

Off-Color Dye Parts can usually be attributed to the dye bath. Your green may be too yellow or your grey too green, but sometimes the alloy/anodize or pretreatment creates the problem.


Some alloys (e.g. 7XXX) produce coatings that have a natural color that may interfere with targeting process. Alloy effects are exacerbated with accelerated anodizing treatments. Those who attempt to dye “additive” hard coat parts are particularly susceptible to this problem.


The more notable pretreatments that interfere with color targeting are shot blasting and acid etching. Both create very low gloss finishes which tends to darken the color hue. Shot blasting can be irregular and this irregularity oftentimes doesn’t show up until the part is processed.

Dye Bath

Over time and use a dye bath may begin to change color. In the case of a black it may revert to its bluish or reddish base color. This usually means the bath has been depleted and/or contaminated. In other cases the color change may be due to decomposition of the dye bath. Some dyes are sensitive to high temperature operation. Other dye baths are multi-component where one component may exhaust faster, fall out of solution, or be more sensitive to contaminants or mould. Because no two dyes are alike, it is good practice to read the data sheet and talk to your chemical vendor for suggested practices.

To our best knowledge, the information and recommendations contained herein are accurate and reliable. However, this information and our recommendations are furnished without warranty, representation, inducement or license of any kind, including, but not limited to the implied warranties of merchantability and fitness for a particular use or purpose. Customers are encouraged to conduct their own tests and to read the product labels carefully before using them. Furthermore, the customer assumes sole liability for any patent infringement that occurs by reason of their following our recommendations or using the information given.


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